During oil or gas well servicing, “snubbing” units are used to insert tubular members into the well being serviced. There are dangers associated with snubbing operations. One danger is that of a “blow out” condition, caused by fluid pressure down hole. Blowout preventers that seal around the tubular members, such as U.S. Pat. No. 3,797,570 (Leutwyler), can be used to protect against such blow out conditions. Blowout preventers are ineffective in dealing with other dangers associated with snubbing operations.